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/* SPDX-License-Identifier: BSD-3-Clause */
/*
* Copyright (C) 2022, 2023 Ferass El Hafidi <vitali64pmemail@protonmail.com>
*/
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#define REQ_PRINT_USAGE /* Require print_usage() from common.h */
#define REQ_ERRPRINT /* Require errprint() from common.h */
#define DESCRIPTION "Copy the last part of files."
#define OPERANDS "[-n number] [file] ..."
#include "common.h"
#ifdef FASESBOX
int tail_main(int argc, char *argv[]) {
#else
int main(int argc, char *argv[]) {
#endif
int argument, i = 1, lines = 10, file_lines = 0;
FILE *file = NULL;
char s[4096], *argv0 = strdup(argv[0]);
while ((argument = getopt(argc, argv, "n:")) != -1) {
if (argument == '?' || argument == ':') {
print_usage(argv[0], DESCRIPTION, OPERANDS, VERSION);
return 1;
}
else if (argument == 'n') {
lines = strtol(optarg, NULL, 10);
if (errno) return errprint(argv[0], "strtol()", errno);
}
} argc -= optind; argv += optind;
if (argc < 1) {
while (read(STDIN_FILENO, s, 4096) > 0)
printf("%s", s);
}
for (i = 0; i != argc; i++) {
if (strcmp(argv[i], "-")) file = fopen(argv[i], "r");
else while (read(STDIN_FILENO, s, 4096) > 0) printf("%s", s);
if (file == NULL)
return errprint(argv[0], argv[i], errno); /* Something went wrong */
while (fgets(s, 4096, file) != NULL)
file_lines++; /* Get number of lines */
fclose(file);
file_lines = file_lines - lines;
if (strcmp(argv[i], "-")) file = fopen(argv[i], "r");
while (fgets(s, 4096, file) != NULL) {
if (errno) return errprint(argv0, argv[i], errno);
if (file_lines == 0) printf("%s", s);
else file_lines--;
}
}
return errprint(argv0, NULL, errno);
}
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